Method for Sending Wake Up Packet

1. A method, comprising: setting, by a first node, a network allocation vector (NAV) according to a frame on a first channel, wherein the first channel is a channel on which a main transceiver of a second node works, wherein the first node is an access point (AP); detecting, by the first node, whether a second channel is idle while the NAV is set, wherein the second channel is a channel on which a wake up receiver of the second node works, wherein the first channel is a wireless transmission channel, and wherein the second channel is a wireless transmission channel; maintaining, by the first node, a first contention window (CW1) on the first channel; generating, by a first node, a backoff count based on CW1; executing backoff based on the backoff count; and sending a wake up packet to the second node on a second channel in response to the backoff ending.

2. The method according to claim 1, wherein the method further comprises: selecting any access category or defining a new access category used for sending the wake up packet.

3. The method according to claim 1, wherein the method further comprises: keeping CW1 unchanged on the second channel in response to the wake up packet being sent unsuccessfully.

4. The method according to claim 1, wherein the first node maintains a second contention window (CW2) on the second channel, wherein CW2 is updated based on a minimum contention window (CW2_min) and a maximum contention window (CW2_max) that are maintained on the second channel; and wherein the method further comprises performing, after the executing backoff based on the backoff count, and sending a wake up packet to the second node on a second channel when backoff ends: updating, in response to the wake up packet being unsuccessfully sent, the current CW2 to (CW2+1)*2−1, wherein the updated CW2 does not exceed CW2_max; or resetting CW2 to CW2_min in response to the wake up packet being sent successfully.

5. The method according to claim 4, wherein CW2_min and CW2_max are specified by an access point (AP).

6. The method according to claim 1, wherein the method further comprises performing, in response to a main transceiver of the first node returning to the first channel to send an 802.11 frame: reading the backoff count maintained on the first channel; executing backoff based on the backoff count; and sending the 802.11 frame on the first channel when backoff ends.

7. A first node, comprising: a main transceiver; one or more processors; and at least one non-transitory computer readable memory connected to the one or more processors and including computer program code, wherein the first node is an access point (AP), and wherein the at least one non-transitory computer readable memory and the computer program code are configured, with the one or more processors, to cause the first node to perform at least: maintaining a first contention window (CW1) on a first channel, wherein the first channel is a channel on which a main transceiver of a second node works; setting a network allocation vector (NAV) according to a frame on the first channel; detecting whether a second channel is idle while the NAV is set, wherein the second channel is a channel on which a wake up receiver of the second node works, wherein the first channel is a wireless transmission channel, and wherein the second channel is a wireless transmission channel; maintaining a first contention window (CW1) on the first channel; generating a backoff count based on CW1; executing backoff based on the backoff count; and sending a wake up packet to the second node on a second channel in response to the backoff ending.

8. The first node according to claim 7, wherein the at least one non-transitory computer readable memory and the computer program code are configured, with the one or more processors, to further cause the first node to select any access category or define a new access category used for sending the wake up packet.

9. The first node according to claim 7, wherein the at least one non-transitory computer readable memory and the computer program code are configured, with the one or more processors, to further cause the first node to keep CW1 unchanged on the second channel in response to the wake up packet being unsuccessfully sent.

10. The first node according to claim 7, wherein the at least one non-transitory computer readable memory and the computer program code are configured, with the one or more processors, to further cause the first node to: maintain a second contention window (CW2) on the second channel, and CW2 is updated based on a minimum contention window (CW2_min) and a maximum contention window (CW2_max) that are maintained on the second channel; update, in response to the wake up packet being unsuccessfully sent, the current CW2 to (CW2+1)*2−1, wherein the updated CW2 does not exceed CW2_max; and reset CW2 to CW2_min in response to the wake up packet being sent successfully.

11. The first node according to claim 10, wherein CW2_min and CW2_max are specified by an access point (AP).

12. The first node according to claim 7, wherein the at least one non-transitory computer readable memory and the computer program code are configured, with the one or more processors, to further cause the first node to perform, in response to the main transceiver of the first node returning to the first channel to send an 802.11 frame: read the backoff count maintained on the first channel; execute backoff based on the backoff count; and cause the main transceiver of the first node send the 802.11 frame on the first channel when backoff ends.

13. An apparatus for sending a wake up packet, the apparatus comprising: one or more processors; and at least one non-transitory computer readable memory connected to the one or more processors and including computer program code, wherein the apparatus is a first node and an access point (AP), and wherein the at least one non-transitory computer readable memory and the computer program code are configured, with the one or more processors, to cause the apparatus to perform at least: set a network allocation vector (NAV) according to a frame on a first channel, wherein the first channel is a channel on which a main transceiver of a second node works; detect whether a second channel is idle while the NAV is set, wherein the second channel is a channel on which a wake up receiver of the second node works, wherein the first channel is a wireless transmission channel, and wherein the second channel is a wireless transmission channel; maintain a first contention window (CW1) on the first channel; generate a backoff count based on CW1; executing backoff based on the backoff count; and sending a wake up packet to the second node on a second channel in response to the backoff ending.

14. The apparatus according to claim 13, wherein the at least one non-transitory computer readable memory and the computer program code are configured, with the one or more processors, to further cause the apparatus to: select any access category or define a new access category used for sending the wake up packet.

15. The apparatus according to claim 13, wherein the at least one non-transitory computer readable memory and the computer program code are configured, with the one or more processors, to further cause the apparatus to: keep CW1 unchanged on the second channel in response to the wake up packet being unsuccessfully sent.

16. The apparatus according to claim 13, wherein the at least one non-transitory computer readable memory and the computer program code are configured, with the one or more processors, to further cause the apparatus to: maintain a second contention window (CW2) on the second channel, wherein CW2 is updated based on a minimum contention window (CW2_min) and a maximum contention window (CW2_max) that are maintained on the second channel; update in response to the wake up packet being unsuccessfully sent, the current CW2 to (CW2+1)*2−1, wherein the updated CW2 does not exceed CW2_max; or reset CW2 to CW2_min in response to the wake up packet being sent successfully.

17. The apparatus according to claim 16, wherein CW2_min and CW2_max are specified by an access point (AP).

18. The apparatus according to claim 13, wherein the at least one non-transitory computer readable memory and the computer program code are configured, with the one or more processors, to further cause the apparatus to perform, in response to a main transceiver of the apparatus returning to the first channel to send an 802.11 frame: read the backoff count maintained on the first channel; execute backoff based on the backoff count; and send the 802.11 frame in response to the backoff ending.